Coherence and Quantum Technology, Department of Physics, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands.
Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven 5600 MB, The Netherlands.
Nat Commun. 2016 Dec 23;7:13769. doi: 10.1038/ncomms13769.
Terahertz (THz) pulses are applied in areas as diverse as materials science, communication and biosensing. Techniques for subwavelength concentration of THz pulses give access to a rapidly growing range of spatial scales and field intensities. Here we experimentally demonstrate a method to generate intense THz pulses on a metal wire, thereby introducing the possibility of wave-guiding and focussing of the full THz pulse energy to subwavelength spotsizes. This enables endoscopic sensing, single-shot subwavelength THz imaging and study of strongly nonlinear THz phenomena. We generate THz surface plasmon polaritons (SPPs) by launching electron bunches onto the tip of a bare metal wire. Bunches with 160 pC charge and ≈6 ps duration yield SPPs with 6-10 ps duration and 0.4±0.1 MV m electric field strength on a 1.5 mm diameter aluminium wire. These are the most intense SPPs reported on a wire. The SPPs are shown to propagate around a 90° bend.
太赫兹（THz）脉冲在材料科学、通信和生物传感等多个领域得到了广泛应用。亚波长聚焦 THz 脉冲的技术可以实现快速扩展的空间尺度和场强。在这里，我们通过在金属丝上产生强太赫兹脉冲，实验证明了一种在金属丝上产生强太赫兹脉冲的方法，从而实现了全太赫兹脉冲能量的波导和聚焦到亚波长光斑尺寸的可能性。这使得内窥感应、单次亚波长太赫兹成像和强太赫兹非线性现象的研究成为可能。我们通过在裸露的金属丝尖端发射电子束来产生太赫兹表面等离子体激元（SPP）。在 1.5 毫米直径的铝丝上，带有 160pC 电荷量和 ≈6ps 持续时间的电子束产生了持续时间为 6-10ps、电场强度为 0.4±0.1MV/m 的 SPP。这是在金属丝上报道的最强 SPP。实验表明，SPP 可以在 90°弯角处传播。
